摘要:

1979 1435Spectroscopic and Structural Studies on Cobalt Complexes of the MethylEsters of Dithiocarbazic and 2-Methyldithiocarbazic Acids. CrystalStructure of [ Co(NH2NHC(=S)SMe)(N H2N=C( S)SMe}2]CI-H20 tBy Anna Monaci and Franco Tarli, Laboratorio Teoria e Struttura Elettronica e Comportamento Spettrochimicodei Composti di Co-ordinazione del C.N.R., Roma, ItalyAnna Maria Manotti Lanfredi, Antonio Tiripicchio," and Marisa Tiripicchio Camellini, istituto diChimica Generale, Universith di Parma, Centro di Studio per la Strutturistica Diffrattometrica del C.N.R.,Parma, ItalyThe ligand behaviour of methyl esters of dithiocarbazic acid NH,NHC(=S)SMe (HL) and of 2-methyldithiocarbazicacid NH,NMeC(=S)SMe (MeL) in cobalt complexes has been investigated. Complexes of Co" and Co'" havebeen prepared under different conditions and characterized by their electronic and i.r.spectra. HL can act as aligand when neutral or when deprotonated (L-) ; MeL can be deprotonated at the terminal N only after co-ordin-ation. The crystal structure of [Co(HL) L,]CI*H,O has been determined by X-ray diffraction methods : crystals aremonoclinic, space group P2,/c, Z = 4, in a unit cell of dimensions a = 12.085(9), b = 8.903(8), c = 17.287(16) A,and p = 104.2(1)". The structure has been solved by Patterson and Fourier methods and refined by block-diagonalfeast squares to R = 0.042 for 1 993 reflections. It consists of cis-octahedral [Co(HL)L,]+ cations, in which oneneutral and two deprotonated molecules of methyl dithiocarbazate act as chelating tigands, chloride anions, andwater molecules, held together by a network of hydrogen bonds.The bond distances in the co-ordinationpolyhedron are : Co-S 2.203(4), Co-N 1.993(6) A for the neutral ligand ; Co-S 2.21 2(5) and 2.21 8(3), Co-N1.977(6) and 1.980(6) A for the deprotonated ligands. The conformation of the three ligands is cis,cis, i.e. withboth NHNH, and SMe groups bent towards the C=S bond.THE ligating properties of N- and S-substituted deriva-tives of dithiocarbazic acid NH,NHC(=S)SH havebeen studied in recent years by us and other workers2Some of their co-ordination compounds have shown bio-logical activity as pesticides3 and, more recently, ascarcinostatic agents.4 The S-met hyl dit hiocarbazatesshow different ligating behaviour with the same metal(e.g.Ni) depending on the type of N-substitution and onthe reaction condition^.^ It was of interest to study thecomplexes of S-methyl dithiocarbazates with cobalt,which can also present different oxidation states depend-ing on the reaction conditions and the co-ordinationenvironment.We started with NH,NHC(=S)SMe (HL) and NH,-NMeC(=S)SMe (MeL); HL can act as a ligand whenneutral or when deprotonated (L-). The anion L-,which is present also in the potassium salt, is character-ized by the disappearance of the bands of v(N-H) a t1 170 cm-l and v(C=S) at 1 010 cm-l in the i.r. spectrum.Among the complexes obtained, [Co( HL)L,]Cl*H,O waschosen for the X-ray structure determination becauseboth neutral and anionic forms of the ligand are presentthus providing an opportunity to study whetherstructural modifications are induced by deprotonation ofthe ligand.The structure of the unco-ordinated ligandhas already been described.6EXPERIMENTALMateria2s.-The ligands HL and MeL were prepared asin refs. 2 and 7 respectively. All other chemicals were com-mercial analytical grade reagents and were used withoutfurther purification. Nitrogen gas was an ultra high-purity commercial product.Preflarataons of the Comjdexes.-Previous studies 8 on thebehaviour of HL in solvents with increasing polarity (anhy-drous ethanol, ethanol, and water) showed that i t is notdeprotonated in anhydrous ethanol. By taking this intoaccount, several complexes of CoIII and CoII containing HLand/or L were prepared.Thus, [Co(HL),]X, (X = C1 orBr) was prepared from COX, (1 mmol in 10 cm3 anhydrousethanol) and HL (3 mmol in 10 cm3 of anhydrous ethanol) ina N, atmosphere. The precipitated compound was filteredoff and dried under N, (yield 65%). The same compoundcan be obtained by working in ethanol acidified with3.7% HC1 (1 cm3) , thus preventing deprotonation of HL;yield 49%. The solid compound is stable under a N,atmosphere.These complexes wereobtained by exposing to air finely powdered [Co(HL),]X, ;yield ca. lOOyo.Treatment of CoCl,*6H,O (3.4 mmolin 15 cm3 ethanol) with HL (10.2 mmol in 15 cm3 ethanol)gave a mixture of [Co(HL),L]Cl, and [Co(HL)L,]Cl*H,O.After crystallization from boiling ethanol, crystals of theless-soluble [Co(HL)L,]Cl*H,O were obtained, yield 20%.This complex was obtained from CoC1,*6H,O(1 mmol in 10 cm3 water) and HL (3 mmol in 100 cm3water) (yield 95%), or from water and any compoundcontaining HL and/or L reported in this work.[Co(HL),]Cl,*H,O. This was prepared from CoCl,*GH,O(2 mmol in 30 cm3 ethanol) and HL (6 mmol in 30 cm3ethanol with 4 cm3 of 37% HCl), by bubbling 0, to increasethe reaction velocity, yield 55%.These complexeswere prepared from the cobalt halide (1.5 mmol in anhy-drous ethanol) and HL (1.8 mmol in 20 cm3 anhydrousethanol).The compounds, precipitated after evaporationof part of the solvent in vucuo (15 mmHg),$ are hygroscopicand can be dried a t 100 "C in vmuo (1 mmHg), yield 37%for X = C1, 54% for X = Br.[CO~~(M~L),,C~,] § was prepared from CoCl,*GH,O (1.6mmol in 10 cms ethanol) and MeL (3 mmol in 40 cm3t (Methyl dithiocarbazate-NsS)bis[methyl dithiocarbazato-(1 -)-NsS]cobalt(~rr) chloride monohydrate.$Throughout this paper: 1 mmHg w 13.6 x 9.8 Pa.Note added at proof: preliminary results of the X-ray crystalanalysis of this compound have shown that i t must be formulatedas [CoII(MeL) BCla] -0.5MeL.[Co(HL),L]X, (X = C1 or Br).[Co(HL)L,]Cl-H,O.[CoL,].[CO~~~(HL),],[CO~~X,~, (X = C1 or Br)1436TABLE 1Analytical dataAnalysis (yo)J.C.S. DaltonCompound Colour C H NRed-brown 12.85 (13.1) 3.85 (3.65) 15.3 (15.3)Brown 14.65 (14.66) 3.80 (3.45) 16.9 (16.95)Brown 12.15 (12.35) 3.05 (2.95) 14.3 (14.4)Brown 15.26 (15.1) 3.90 (3.80) 17.8 (17.6)Brown 17.1 (17.05) 3.65 (3.60) 19.7 (19.9)Dark brown 10.2 (9.90) 2.85 (2.50) 11.45 (11.55)Dark brown 7.26 (7.25) 1.80 (1.85) 8.45 (8.45)Red-brown 17.5 (17.2) 4.85 (4.80) 13.35 (13.4)Brown 17.15 (17.25) 3.80 (3.70) 13.35 (13.4)Pink 16.9 (16.85) 3.75 (3.75) 12.95 (13.1)Blue 19.15 (19.15) 4.40 (4.30) 15.0 (14.9)Dark brown 14.55 (14.05) 3.30 (3.15) 10.8 (10.95)Dark brown 10.4 (10.45) 2.40 (2.35) 8.00 (8.10)* Calculated values are given in parentheses.c119.15 (19.35)14.25 (14.3)7.30 (7.45)29.15 (29.3)16.85 (16.95)15.3 (15.05)27.5 (27.7)ethanol) in a N, atmosphere.The compound precipitatedafter evaporation of part of the solvent in a stream of N,,yield 82%. The same compound was obtained by workingwith different mol ratios of the reagents (e.g. 1 : 3).This was obtained from Co[S04]*7H,0(1.1 mmol in 10 cm3 methanol) and MeL (3.3 mmol in 20cm3 methanol) in a N, atmosphere.The solution wasevaporated to dryness by N, bubbling. The excess ofMeL was sublimed off a t 85 "C in uacuo ( 1 mmHg), yieldThis complex was prepared from CoBr,(1 mmol in 20 cm3 ethanol) and MeL (3 mmol in 40 cm3 ofethanol) in a N, atmosphere. The compound precipitatedafter evaporation of the solvent by N, bubbling. It wasfiltered off and dried in a stream of N,, yield 76%. Thesolid is stable under N,.[Co(MeL),(MeL - H)]Br,. This was obtained in ca.lOOyo yield by exposing finely powdered [Co(MeL),]Br,to air. The deprotonated ligand [MeGH = NHNMeC(=S)SMe] necessarily involves the loss of one hydrogen fromthe co-ordinated terminal N.We have already observedthe same behaviour for MeL in the corresponding nickelcomplexes.1cThis complex was prepared fromCoC1,*6H,O (0.7 mmol in 20 cm3 ethanol with 1 cm3 of 37%HCl) and MeL (2.1 mmol in 20 cm3 ethanol with 1 cm3 of37% HC1). Crystals of the compound separated after somedays, yield 49%.[CO~*~(M~L),],[CO~~X,], (X = C1 or Br). These com-plexes were obtained from the cobalt halide (2.3 mmol in15 cm3 water) and MeL (2.7 mmol in 60 cm3 water). Thecompounds precipitated after evaporation of part of thesolvent in uacuo ( 1 mmHg), yield 32% for X = C1, 47% forX == Br.In general, all the compounds described in this workdissolve only in polar solvents, and undergo modifications.Analytical data are given in Table 1.Physical Measurements.-The visible reflectance spectra ofthe finely powdered solids were recorded on a Beckman DK2spectrophotometer fitted with a standard reflectanceattachment and MgO in the reference beam.Solutionspectra were obtained for ethanol solutions a t room temper-ature on a Beckmann DK2 spectrophotometer (concen-tration range 10-s-10-3 mol dm-3). Infrared spectra wererecorded on a Perkin-Elmer model 62 1 spectrophotometeras Nujol or poly(chlorotrifluoroethy1ene) mulls. Magneticmeasurements were performed on solid samples with aGouy balance calibrated with Hg[Co(SCN),] .[Co(MeL),(SO,)].90%.[Co(MeL),]Br,.[Co(MeL),]C13*3H,0.Crystal DUtU.-C,H,,C1CON60S6, M = 476.93, Mono-clinic, a = 12.085(9), b = 8.903(8), c = 17.287(16) A.p = 104.2(1)", U = 1803(3) A3, 2 = 4, D, = 1.76 g crnb3,F(000) = 976, Mo-K, radiation, X = 0.710 69 A, p(Mo-K,) = 17.73 cm-l, space group P2Jc from systematicabsences.Preliminary unit-cell parameters were determined fromrotation and Weissenberg photographs, and refined by aleast-squares procedure applied to the diffractometermeasurements of 8 for 15 reflections.Intensity Data.-Intensity data were collected on aSiemens AED single-crystal diffractometer, by use ofzirconium-filtered Mo-K, radiation and the w-20 scantechnique. A prismatic crystal of dimensions ca.0.15 x0.25 x 0.35 mm was aligned with its b axis along the t$axis of the diffractometer and all the reflections with20 < 50" were measured.Of 3 179 independent reflections,1 993 having I > 2 4 1 ) were considered observed and usedin the analysis. Intensity data were corrected for Lorentzand polarization factors, but not for absorption effects.The absolute scale and the overall temperature factor weredetermined by Wilson's method.Structure Determination and Refinement .-The structurewas solved by Patterson and Fourier methods and refinedby block-diagonal least squares, first with isotropic, thenwith anisotropic, thermal parameters. Hydrogen atomswere located directly from a AF map. Further least-squares cycles were computed, including isotropic thermalparameters for the hydrogen atoms. Unit weights werechosen a t every stage of the refinement by analyzing thevariation of lAFl with lF,,l.The final R was 0.042 (observedreflections only). Atomic scattering factors for non-hydro-gen atoms were taken from ref. 9 and for hydrogen atomsfrom ref. 10. Final atomic co-ordinates are given in Table2. Thermal parameters, observed and calculated structurefactors, hydrogen-atom parameters, details of hydrogenbonding, rotation angles of SMe groups, and electronicand magnetic data are in Supplementary Publication No.SUP 22523 (21 pp.).*All the calculations were performed on a CYBER 76computer of the Centro di Calcalo Interuniversitariodell' Italia Nord-Orientale (Bologna).RESULTS AND DISCUSSIONX-Ray Structure of [Co(HL)L,]Cl*H,O.-The structureis shown in Figure 1; bond distances and angles areIndex issue.* For details see Notices to Authors No.7, J.C.S. Dalton, 19781979 1437d Ht1221FIGURE 1 Structure of [Co(HL)L,]CI.H,O with the atom-labelling systemgiven in Table 3. The structure consists of octahedral[Co(HL)L,]+ cations linked to the chloride anions andto the water molecules by a network of hydrogen bonds.One neutral and two deprotonated methyl dithiocarb-azate molecules, acting as chelating ligands throughsulphur and nitrogen, co-ordinate to CoIII in a cis-octahedrp.1 arrangement. The S and N atoms of theCoIII S,N, chromophore are at the corners of two nearlyequilateral triangles [N (2 1 )-N (22) 2.858 (6), N (22) -N(23) 2.825(7), N(21)-N(23) 2.811(6), S(21)-S(22)TABLE 2Fractional atomic co-ordinates for non-hydrogen atoms( x lo4) with estimated standard deviations in parenthesesxla2 909( 1)6 150( 1)1826(2)1 697(1)3 208( 1)2 144( 1)1 960(1)1 693( 1)3 205(4)3 590(4)4 024(4)3 987(4)3 527(4)902(6)1872(5)3 !88(4)688(5)4 848(3)3 979(3)2 349(5)2 499(4)Y Ib2 172(1)2 326(2)229(2)792(2)1458(2)7 042(2)4 057(2)1932(6)2 750(5)- 695(2)- 182(5)479(5)3 549(5)5 025(6)-1 128(9)-110(8)1103(7)200(6)7 207(8)5 302(6)2 104(4)ZlC1 303(1)2 489( 1)3 530(1)1 772(1)- 903( 1)57U)401(1)1 l40(l)3 045(3)2 423(2)595(2)1 354(2)692(2)939(2)3 013(4)2 772(3)-1 553(3)1(3)758(4)767(3)4 521(2)3.197 (4), S (22)-S (23) 3.108(3), S (21)-S(23) 3.105(4) A],which are almost parallel, the dihedral angle they formbeing 179".The distortion of the co-ordination octa-hedron is mainly due to the different size of the ligandatoms ; nevertheless this distortion does not influencethe dihedral angles between the main planes of theoctahedron which are near to 90". The conformationof the three independent ligands is &,cis, i.e. both theNH, and methyl groups are cis with respect to the C=Sbond. This conformation is different from the &,transone found for the uncomplexed *molecule.6 There areno regular differences between corresponding bonddistances and angles in the neutral and deprotonatedligands, even if some of these differences are significant.In all the three complexed molecules the N-N distancesand the N-N-C, S-C-S, and N-C-SMe angles are signi-ficantly different with respect to those found for theuncomplexed ester: the lengthening of the N-N dis-tances and the narrowing of the N-N-C angles in thechelating esters are probably related to the chelationto the metal, while the variations of the S-C-S andN-C-SMe angles are probably related to steric effectsdue to the transition from the cis,trans to cis,cis con-formation.In all the ligands the hydrogen atoms of theSMe groups are gauche with respect to the S-CH, bond.The NCSS group is strictly planar in the deprotonatedanions (Table 4), with small but significant displacementfrom planarity in the neutral molecule indicating thatthere is more conjugation through the NCSS group inthe anions.The analysis of the planarity shows tha1438TABLE 3Bond distances (A) and angles (")(a) In the co-ordination polyhedronCwN(21)Co-N (22)co- Is (23)N (2 l)-Co-N( 22)N (2 l)-Co-N ( 23)N( 2 l)-Co-S( 21)N ( 2 l)-Co-S (23)N ( 22)-Co-N ( 23)N (23)-Co-S (23)N (2 l)-Co-S (2 2)N ( 22)-Co-S( 2 1)(b) In the organ1.977( 4)1.980(6)1.993( 6)92.5( 2)90.2(2)86.5 (2)9 1.8( 2)178.4 (2)90.7(2)9 2 4 1)87.4( 1)ic ligandsN( 2 1)-N( 11)N( 11)-C(21)C( 2 1)-s (21)C( 2 1)-S( 1 1)S( 1 l ) - C ( l 1)N (22)-N ( 1 2)N(12)-C(22)C( 22)-S(22) c (2 2) -s ( 1 2) s ( 1 2)-c( 1 2)N ( 23)-N ( 1 3)N( 13)-C(23)C(23)-S(23)C(23)-S( 13)S( 13)-C( 13)N( 2 1)-N( 1 l)-C( 2 1)N( 11)-C( 21)-S(21)N( 11)-C(Z1)-S( 11)N( 13)-H( 131S( ll)-C(2l)-S(21)C( 2 1)-s (1 1)-C( 1 1)N( 1 1)-N( 21)-H( 2 1 1)N (1 1)-N( 21)-H( 212)N (2 2)-N ( 1 2)-C (2 2)N( 12)-C( 22)-S ( 12)N(12)-C(22)-S(22)S( 12)-C( 22)-S( 22)C(22)-S( 12)-C( 12)N( 12)-N(22)-H(221)N ( 12)-N (22)-H (222)N(23)-N(13)-C(23)N ( 1 3)-C( 23)-S (23)N (1 3)-C( 23)-S( 13)C(23)-S( 13)-C( 13)N ( 13)-N (23)-H (23 1)N( 13)-N( 23)-H (232)H(23 1)-N(23)-H( 232)S(23)-C(23)-S( 13)1.466(7)1.264 (8)1.737(6)1.769(6)1.737( 8)1.449( 5)1.297 (7)1.708( 7)1.760( 6)1.803 (7)1.447 ( 6)1.304( 9)1.703(6)1.738( 6)1.798 (9)1.08( 6)1 13.2 (5)126.5 (5)1 12.9( 4)120.7 (4)103.1(3)114(3)108(3)1 1 4.8( 4)1 14.0( 4)124.8( 4)12 1.3( 3)102.6 (3)106(3)106(4)1 16.3 (4)124.2 (4)114.4(4)12 1.3 (3)102.9(3)106(3)llO(3)97(4)(c) In the water molecule0 (W)-H (31 0.79(5)0 (w )-H (4) 0.88 (71co-s (2 1) co-s ( 22)s (2 1)-co-s ( 23)Co-S(23)N (22)-Co-S ( 23)N ( 2 3) -CO-S ( 2 1 )S( 22)-Co-N( 22)S ( 2 2)-Co-N (23)S(22)-CO- S(21) s (22)-co-s (23)N( 21)-H (2 1 1)N( 3 1)-H (2 12)C( 11)-H( 11 1)C( 1 1)-H( 1 12)C( 11)-H( 113)N( 22)-H(221)N(22)-H( 222)C( l2)-H( 121)C( 12)-H( 122)C( 12)-H(123)N(23)-H(231)N (23)-H (232)C( 13)-H( 131)C( 13)-H( 132)C( 13)-H ( 133)H ( 2 1 1)-N( 2 1)-H( 2 12)S( ll)-C(ll)-H( 111)S( 11)-C( 11)-H( 112)S( 1 l)-C( 1 1) -H ( 1 13)H( 111)-C( 11)-H( 112)H( 11 1)-C( 11)-H( 113)H( 112)-C( 1 1)-H( 113)H (2 2 1) -N ( 22)-H (2 22)S( 12)-C( 12)-H (1 2 1)S ( 12)-C( 12)-H( 122)S( 1 2)-C ( 1 2)-H ( 1 23)H ( 1 2 1)-C( 1 2)-H ( 1 22)H( 12 1)-C( 12)-H ( 123)H ( 122)-C( 12)-H ( 123)N( 23)-N( 13)-H ( 13)C(23)-N(13)-H(13)S( 13)-C( 13)-H( 13 1)S ( 13)-C ( 1 3)-H ( 1 3 2)S ( 1 3)-C( 1 3)-H ( 1 3 3)H( 13 1)-C( 13)-H( 132)H ( 13 1)-C( 13)-H ( 133)H ( 1 3 2)-C( 13)-H ( 1 3 3)2.2 12 (5)2.2 18( 3)2.203 (4)89.4(1)L75.3( 1)175.3( 1)86.5(1)92.4(1)89.3(1)91.0( 1)1.09 (6)1.02( 5)0.85(7)0.95(9)1.07(7)1.02(5)0.8 1 (5)1.12(5)1 .OO( 7)1.01(7)0.95(5)0.92(5)0.97( 6)0.90( 5)0.84( 6)103(5)129(5)121(5)104(7)lOl(6)l l O ( 5 )105(3)103(4)116(4)105(4)l l O ( 5 )116(5)115(3)129(3)106(4)116(4)104(4)109(5)llO(6)111(6)97(4)97(6)111(6)the plane running through the NCSS conjugated systemleaves the N(22) and C(12) atoms on the same side andthe terminal N atoms and the C atoms of the SMe groupsof the other two ligands on opposite sides.The three five-membered chelating rings are notperfectly planar (Table 4).They show slight butdifferent puckering as indicated by the puckering para-meters calculated following ref. 11 :Ring 4alk 4aI0N(21)N(ll)C(2l)S(211Co 0.158 341N(221N( 12V2(22)S(22Eo 0.180 33 1N(23)N( 13)C(23)S(23)Co 0.054 138The conformation of these groups is intermediatebetween the envelope and half-chair.J.C.S. DaltonIt is worthy of note that the neutral ligand forms theless puckered chelation ring, while it is the only ligandwhich is not perfectly planar.The packing is determined by a network of inter-molecular hydrogen bmds involving the chloride ions,the water molecules, and the N atoms of the ligands.TABLE 4Equations of the best least-squares planes in the formmX + n Y + $2 = d where X,Y,Z are co-ordinates(A) referred to orthogonal axes X EE x , Y y, and Zperpendicular to X , Y .Deviations (A) of relevantatoms from the planes are in square bracketsm n P d0.6273 - 0.7788 - 0.0070 0.2454Plane (I): C(21), S(11), S(21), N(11)[C(21) 0.001(6), S(11) -0.001(2), S(21) -0.001(2), N(11)-0.001(5), N(21) -0.103(5), C(11) 0.384(8)]Plane (11): C(22), S(12), S(22), N(12)0.6303 0.7437 -0.2229 2.5617[C(22) -0.002(5), S(12) 0.001(2), S(22) 0.001(2), N(12)0.001(5), N(22) -0.075(5), C(12) -0.214(7)]Plane (111): C(23), S(13), S(23), N(13)-0.1394 -0.3907 -0.9099 -3.3702[C(23) -0.019(5), S(13) 0.003(2), S(23) 0.003(2), N(13)0.014(4), N(23) 0.089(4), C(13) -0.364(7), H(13) -0.10(5)JPlane (IV): S(21), C(21), N(11), N(21)0.2351 0.6635 -0,7474 -0.0333[S(21) 0.001(2), C(21) -0.020(6), N(11) 0.023(5), N(21)-0.003(5), CO 0.213(5)]Plane \V): S(22), C(22), N(12), N(22)0.6298 0.7541 - 0.1862 2.5765[S(22) 0.001(2), C(22) -0.016(5), N(12) 0.020(5), N(22)-0.004( 5), CO 0.341(1)]Plane (VI): S(23), C(23), N(13), N(23)-0.1642 -0.3489 -0.9227 -3.2791[S(23) -0.001(2), C(23) 0.004(5), N(13) --0.004(4), N(23)0.001(4), Co 0.103(2)]Electronic Spectra.-The cobalt (111) complexes exhibitelectronic spectra which fit pseudo-octahedral patternsfor a d6 configuration of =Oh geometry, according totheir diamagnetism.The nearly coincident values forthe electronic transitions of all the compounds indicatethe same co-ordination environment in each case. Thechromophore is, indeed, cis-Co111N3S3, as indicated by theX-ray structure determination of [Co (HL) L2]C1*H20.The close similarity of the electronic spectra of com-pounds containing neutral and/or anionic ligands isindicative of high charge delocalization in the N=C(LS)SMe moiety as already suggested by photo-electron spectral measurements on nickel S-met hyldithiocarbazates l2 and clearly confirmed by X-raystructural data.The spectroscopic parameters A = lODq = 19 900cm-l, B = 389 cm-l, and p = 0.355 (calculated follow-ing ref.13) for [Co(MeL),]C13-3H,0 can be extended toall the cobalt(II1) compounds. The low value of pagrees with the presence of S in the co-ordinationsphere. The electronic spectra of [COII~(HL),],[COIIX~]~and [CO~I~(M~L),]~[COI~X,]~ (X = C1 or Br) exhibi1979 1439features which are characteristic of both octahedralCoTII and tetrahedral CoII.The complexes [Co(HL),]X, (X = C1 or Br), [Co-(MeL),] Br,, [CoII( MeL),.,Cl,] , and [Co(MeL),(SO,)] exhi-bit electronic spectra which fit pseudo-octahedralmodels for a d7 configuration, according to their mag-netic moments. The coincident spectra of [Co(HL),]Cl,and [Co(HL),]Br, suggest that both compounds have thesame chromophore. This can be reasonably consideredHL * MeL3 280 3 290s3 210 3 235m3 170 3 19Ow1600 160815801 5201155s 11001010 1030 (sh)1 050s975 (sh) 965 (sh)945s 945sCC0WL)aI-C13.H203 0602 620br1620 (sh)1 60015701070s1035m970vs955sof O h symmetry due to the presence of C1 and 0 in theco-ordination environment, respectively.Infrared Spectra (Tables 5 and 6).-All the complexesshow v(NH,) and 6(NH,) frequencies and bands attri-butable to the NCSS group, in the 900-1 200 cm-lregion, split and lowered upon co-ordination, confirmingthe N,S co-ordination.The complexes [CoIII(HL),],-[CoIICl,] , and [CoIIT( MeL),] ,[CoIICl,], show absorptionfrequencies comparable with those of [Co(HL),]Cl,*H,OTABLE 5Infrared spectra (cm-1) of the cobalt(rI1) complexes3 380br3 0402 590br16451 6001590 (sh)1095m1015m975s955w[Co(HL) 33 a-[cOCI4Ia3 4003 0601 600br1070s1035m985vs960s. .[Co(MeL) a] 2- [Co(HL) L21-[CoC1,I3 [Co(HL),L]Cl, Cl*H203 4003 070 3 160 (sh)3 040w1 600br 1610 16101 590 1 585151Ow 1510w1070 (sh) 1070 (sh)1 090s 1 060s 1 060s1015 1010 (sh)975vs 980s 960s995 (sh) 990960 (sh) 950 950 (sh)915 (sh) 915 (sh)P L 3 I3 2001 5801520s1235m995s960s915mTentativeassignmentsV(0-H)v(N-H)v(NCSS) + V(c=S)v(CIILS)vnaym[C(S-)-SMe]v(N-N)v(C-S)Vsgm [C (S-) -SMe]* Previous reports: M.F. Iskander, El Sayed, and L. El Sayed, J. Inovg. Nuclear Chem., 1971, 33, 4253; D. Fak-Michalska andB. B. Kedzia, Bull. Acad. Polon Sci., 1976, 24, 393.TABLE 6Infrared (cm-') spectra of the cobalt(r1) complexesTentative[Co( MeL) 2.aC12] [Co(MeL),( SO,)] * [Co(MeL) 3]Br2 assignments [Co(HL) 3Ich3 145 v(N-H) 3 100 3 085 3 2083 040 3 156 3 1003 116 3 0481615 1616 1 605 1617 WH2)1 6001 080s 1 096s 1096vs 1 lOOm v(NCSS) + v(C=S)1 084 IS)V ( c - S ) 970 996s 992vs 1 ooovs964s 964vs 980s960vs 960s 960vs 960s v(N-N)896m 905m* SO stretching frequencies v1 at 1 015vs, v3 a t 1 036s, 1 lOOvs, 1 104vs, and 1 145s, and vp at 598vs, 628m, and 652 cm-'.to be CoIIN,S3, as suggested by their easy oxidation inthe air in the solid state to [Co(HL),L]X,, whose chromo-phore is Co*11N3S3.The reflectance spectra of [Co-(HL),]X, and [Co(HL),L]X, are given in Figure 2.A = 9 100 cm-l (ref. 14) for both [Co(HL),]X, and [Co-(MeL),]Br, indicates the same ligand-field strength forboth these ligands in cobalt(I1) complexes, as alreadyobserved for the nickel(I1) complexe~.~ The stoicheio-metries of the compounds [CoII(MeL),.,Cl,] and [Co-(MeL),(SO,)] suggest co-ordination of the anions, as isalso indicated by the electronic spectra.The broaden-ing of the first spin-allowed band and the splitting of thesecond spin-allowed band indicate a significant loweringand [Co(MeL),]C1,*3H20, confirming that they possessthe same co-ordination sphere, as already suggested bythe electronic spectra.The presence of the deprotonated ligand L [NH,N=C-(S-)SMe] in [Co(HL),L]Cl,, [Co(HL)L,]Cl*H,O, and[CoL,] is accompanied by the appearance of a band, inthe 1500-1 550 cm-l region, which is essentially a CNvibration with enhanced double-bond character.More-over, for [CoL,] v(C=S) disappears and a new band,assignable to vaY,[C(S-)SMe] appears at 995 cm-l. Thesame band is also present in the spectra of all compoundscontaining L .In the spectrum of [Co(MeL),(SO,)], bands indicatin1440 J.C.S. Dalton1 I I500 1000 1500k/nmFIGURE 2 Reflectance spectra of (a) [Co(HL),]X, and (b)[Co(HL),L]X, (X = C1 or Br)co-ordination of the SO, group are also present. Thesplitting of v3 and vp suggests a bridging co-ordination.15We thank Professor M. Nardelli for his interest in thiswork, and Mr. M. Zugarini for help in preparing andcharacterizing the compounds,[8/1122 Received, 16th June, 19781REFERENCES1 C. Battistoni, G. Mattogno, A. Monaci, and F. Tarli, (a) J .Inorg. Nuclear Chem., 1971, 33, 3815; (b) Inorg. Nuclear Chem.Letters, 1971, 7 , 981; (c) ibid., p. 1081.M. Das and S. E. Livingstone, Inorg. Chim. Acta, 1976, 19,5 and refs. therein.U.S.P. 3,458,638; B.P. 963,924 and 918,367; Jap. P.21,74411963, 4,51811962, 6,67711964, 22,56911963, and 19,114/1963.M. Akbar Ali and S. E. Livingstone, Co-ordination Chem.Rev., 1973, 13, 126.A. M. Manotti Lanfredi, A. Tiripicchio, M. TiripicchioCamellini, A. Monaci, and F. Tarli, J.C.S. Dalton, 1977, 417.K. A. Jensen, U. Anthoni, and A. Holm, Acta Chem. Scand.,1969,28, 1916. * A. Monaci and F. Tarli, J.C.S. Dalton, in the press.Q D. T. Cromer and J. B. Mann, Acta Cryst., 1968, A24, 321.10 R. F. Stewart, E. R. Davidson, and W. T. Simpson, J . Chem.11 D. Cremer and J. A. Pople, J . Amer. Chem. SOC., 1975, 97,12 C. Battistoni, M. Bossa, C. Furlani, and G. Mattogno, J .13 A. 13. P. Lever, Inorganic Electronic Spectroscopy,’14 E. Konig, Structure and Bonding, 1971, 9, 175.16 K. Nakamoto, ‘ Infrared Spectra of Inorganic and Co-6 A. Monaci and F. Tarli, unpublished work.Phys., 1965, 42, 3175.1354.Electron Spectroscopy, 197$, 2, 355.Elsevier, Amsterdam, 1968.ordination Compounds,’ Wiley, New York, 1963, p. 174

ISSN:1477-9226    

DOI:10.1039/DT9790001435

出版商:RSC    

年代:1979

数据来源: RSC